[lammps-users] interaction between fix rigid and fix spring

Hi all,

I’m trying to simulate friction by dragging a tip along some surface by applying a harmonic force in the direction of motion. I’d like to do this by using fix rigid on the tip, and then using fix spring to couple to tip to an atom (I’ll refer to this as the bob) which moves with constant velocity. My problem is as follows. When the bob moves across the periodic boundary all hell breaks loose. I don’t really know how to descibe it, but the tip vibrates out of control and the simulation dies shortly after due to lose atoms. I’m not sure if this is considered a bug, or just something that LAMMPS is incapable of doing. Any ideas?

tether.zip (1.79 KB)

Ah. I figured out a work-around. I just need to slide the sample, rather than sliding the tip. Thanks anyhow.